1. Field of the Invention
The present invention relates to the field of transfer function generators. More specifically, the present invention relates to a low voltage, high frequency cubic function generator.
2. Description of the Related Art
Function generators are circuits having an output-input characteristic which can be set to approximate a given curve. Circuits that generate an output having a cubic relationship to the input are known as cubic function generators.
Function generators are used for a variety of purposes. For example, in wireless communication systems, a function generator may be used to tune a power amplifier to obtain the desired output from the power amplifier. The function generator provides a tuning signal to the power amplifier to offset the natural behavior of the amplifier.
In many systems today, especially in the digital environment, function generators are required to perform at high speeds. For example, many circuits operate at frequencies in the gigahertz range. In addition to the speed requirements, many digital systems are low voltage, requiring a function generator capable of operating at approximately 2 volts. If the function generator only needs to produce a quadratic function, the voltage criteria is easily met. However, existing circuits do not meet these specifications when a cubic function is required.
What is needed is a compact, cubic function generator capable of operating at high frequencies and low voltages. Specifically, a circuit is required that generates a cubic function while operating at approximately 2 volts and at frequencies up to and including the gigahertz range.